Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can describe an observer’s reference frame by naming the observer, the origin and the positive direction. (Guide: “Every measurement has an observer”)
- I can explain why two observers can both be right when they measure different velocities for the same object. (Guide: Worked example 1)
- I can say what makes a frame inertial and give an everyday example of a frame that is not. (Guide: “Inertial frames”)
- I can explain why relative-velocity problems in this course stay on one straight line. (Guide: “Relative velocity along one line”)
Skills
- I can use v_AC = v_AB + v_BC and v_BA = −v_AB with signed velocities. (Guide: Figure 1; Practice Q1, Q2)
- I can convert positions and displacements from the ground frame into a moving observer’s frame. (Guide: “Converting positions and displacements”; Practice Q4, Q6)
- I can find a meeting or overtaking time by working in the frame of one of the moving objects. (Guide: Worked example 2; Practice Q4)
- I can derive a symbolic expression for a trip on a moving walkway or current, and test it with a limiting case. (Practice Q5)
- I can sketch a velocity–time graph as seen from a frame moving at constant velocity by shifting the original graph. (Guide: Figure 2; Practice Q3)
Reasoning
- I can show with algebra that an observer moving at constant velocity measures the same acceleration as the ground. (Guide: “Acceleration is the same for every inertial observer”)
- I can use data from two frames to support or reject a claim about acceleration. (Practice Q6)
- I can explain why a falling object takes the same time to land whichever inertial frame I use. (Practice Q7)
- I can spot when objects approach each other and use the sum of their speeds, not the difference. (Guide: Worked example 2; Practice Q2, Q4)
All ticked? Move on to Topic 1.5, Vectors and Motion in Two Dimensions, or return to the course roadmap.